This invention relates to a fuel tank for vehicles, particularly passengers cars, of the type having a filler neck which, in the area of a connection to the fuel tank, is guided around the upper edge of a body part or chassis part adjoining the fuel tank and penetrates a lateral fuel tank wall, a partial area of the filler neck projecting into the fuel tank interior.
European Patent Document EP 0 067 652 A1 shows a fuel tank for vehicles, particularly passenger cars, having a filler neck which, in the area of its connection to the fuel tank, extends along the upper edge of an adjoining hollow support and penetrates a lateral fuel tank wall, a partial area of the filler neck projecting into the tank interior.
Caused by the height dimension of the adjoining body-side hollow support, the filler neck extending around the upper edge of the hollow support is connected to the fuel tank at a relatively high level.
The end of the tube-shaped filler neck, which projects only slightly into the tank interior, defines by means of the highest point at which displaced air can emerge, the maximal filling level H of the fuel tank. In the case of this arrangement, the maximal filling level H is situated relatively close to the upper fuel tank wall, specifically above the upper edge of the body-side hollow support so that only a relatively small expansion volume exists above the maximal filling level. However, in order to provide a perfect operation of the fuel tank and to avoid a flowing-out of fuel particularly at high temperatures and/or in an oblique position of the vehicle, an expansion volume is required which amounts to approximately 10% of the total tank interior.
It is an object of the invention to take such measures on a fuel tank arranged adjacent to a relatively high-level body part or chassis part and provided with a filler neck that the maximal filling level can be lowered below the upper edge of the adjoining body part or chassis part and therefore a sufficient expansion volume of the fuel tank is ensured.
According to the invention, this object is achieved by providing a fuel tank assembly of the above noted type wherein an end of the filler neck which projects into the tank interior and a filling ventilation extend below a plane defined by an upper edge of the adjoining body part or chassis part, the maximal filling level being determinable by the highest point of the filling ventilation situated in the tank interior, and wherein the free end of the filler neck extends no higher than at the level of the filling height or lower.
Principal advantages achieved by means of the invention are that, as the result of the extending down of a filling ventilation and of the free end of the filler neck projecting into the tank interior to below the level of the upper edge of the adjoining body part or chassis part, the maximal filling level can be lowered so that, also in the case of these unfavorable conditions, an expansion volume of approximately 10% of the container volume is ensured. The filler neck can be fixedly connected with the fuel tank.
Advantageously, the filler neck is constructed as a plug-type filler neck; that is, it is only subsequently plugged into the already mounted fuel tank. For this purpose, the fuel tank is provided with a receiving neck which is fixed on the exterior side of the fuel tank by way of a collar. The receiving neck comprises an exterior first section with a sealing element fastened to it which interacts with the guided-through filler neck.
The second section of the receiving neck, which projects relatively far into the tank interior, is extended diagonally downward by means of a curved section and is used as a guide for the interior filler neck. In the area of the receiving neck, the filler neck, at least in sections, has a flexible section which is formed by a corrugated pipe or by a rubber part. The flexible section can be formed by an end piece or an intermediate piece which is connected to a straight-line section of the filler neck. In the starting condition (delivery condition), the filler neck has a straight-line shape and assumes a curved shape only when it is plugged into the exterior receiving neck. Advantageously, an interior filling ventilation is provided for the filler neck, whereby the mounting is facilitated, the emission is decreased and the costs are reduced.
In the case of the interior filling ventilation, the ventilation pipe extends inside the filler neck and, in sections, also has a flexible section.
However, the lowering of the maximal filling level H of the fuel tank functions also in the case of an exterior filling ventilation. The highest point of the filling ventilation at which displaced air can flow out defines the maximal filling level of the fuel tank. The filler neck is guided so far downward that it reaches no higher than to this level or is situated lower.
The filler neck projects over the receiving neck in the direction of the tank interior. By providing different lengths for the filler neck and/or the filling ventilation, when the fuel tanks are identical, different maximal filling levels can be implemented (for example, small car--small tank content). By means of the extending-down of the filler neck and of the filling ventilation, all filling levels can be implemented at the level of the entry point of the filler neck and below it.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.